80w or 110w LED High Bay for 30x64x12?

TheBarn · Jul 4, 2018

I have a 30x64x12 pole barn with an unfinished interior with an open ceiling and exposed trusses. After reading over the Lighting Layout and Best Fixture Ever threads, I am deciding between the GreenTek 110w High Bays with 16,400 lumens or the 80w LumeGen 10,400 lumen high bay. Sorry, but I don't have enough posts yet to give you the links. Thanks to Platonic Solid and all the others who have put their time and energy into those threads.

Is a 110 watt fixture appropriate for a 12' mounting height, or is the 80w a better choice?

Do the reflectance values change from 70/50/20 if the interior walls are light gray and there is no ceiling just exposed trusses and light gray underside of the roofing material?

Plugging in 70/50/20 into the visual 3d lighting tool, 15 (3 rows of 5) of the 110w Greenteks is 99 fc. Using IBH 18000LM SD080 MD OZ10 30K 80CRI as the comparable fixture.

Plugging in 70/50/20 with the 80w LumeGens requires 21 fixtures (3 rows of 7) for 93 fc. Using IBH 12000LM SD080 MD OZ10 30K 80CRI as the comparable fixture.

Essentially, the 110w GreenTeks seem like the correct choice, but I am not sure if I am looking at this correctly with regards to ceiling height.

Thanks for your help!

cybrdyke · Jul 4, 2018

You have virtually no reflectances at all. I'd set the wall to 20 and floor to 20 and the ceiling to 10 or 0. Then see how it looks.
16,000 lumens is a lot from 12'. Personally, I'd prefer the smaller one, but it's your space and your money.
How even is the lighting? What kind of variance do you get from point to point, especially in the middle of the floor?

CD

TheBarn · Jul 4, 2018

Knocking down the reflectance values to 20/20/20 gives 83 fc with 15 of the GreenTek fixtures, or 99 fc with 18 fixtures.

These 20/20/20 reflectance values would also change the LumeGens to 24 (3 rows of 8) for 89fc.

However, I do not know how to determine how even that light would be for either fixture.

cybrdyke · Jul 4, 2018

Is there a point by point option, or an isobar option on the program you are using?
CD

TheBarn · Jul 4, 2018

I am just using this Visual Interior Tool which gives basic layout info. I don't know how to do the next steps.

cybrdyke · Jul 4, 2018

Gotcha. It prolly automatically spaces them for optimum coverage. 89 fc is alot.
CD

wssix99 · Jul 5, 2018

TheBarn said:
Essentially, the 110w GreenTeks seem like the correct choice, but I am not sure if I am looking at this correctly with regards to ceiling height.

You need regular fixtures also and NOT "high bay." High bay situations are like what you see in big box stores: (12' is way short of that)

High bay fixtures just have a narrow angle off the reflectors, so with if you mount them too low, you'll get inconsistent lighting and issues with shadows. This will probably be enhanced because the rooms reflectivity.

Regular fixtures should also be a lot less expensive!

TheBarn · Jul 5, 2018

wssix99 said:
You need regular fixtures also and NOT "high bay." High bay situations are like what you see in big box stores: (12' is way short of that)

Ok, I will look into that. I had seen some builds on the light fixture layout thread where the 80w high bays were used with a 10' ceiling height. I will look into regular fixtures for my application too. Thanks.

yeldogt · Jul 5, 2018

The high bay lighting is ... "high bay" -- it needs to be up high so not only will the light disperse .. but it will not act as a sun and blind.

Personally -- I prefer long lengths of strip lighting.

Platonic Solid · Jul 5, 2018

TheBarn - Go with the GreenTek 110W 3x5 pattern.

ddawg16 · Jul 5, 2018

I'm guessing you are going to leave the ceiling open?

If so, you need to take into account those scissor joists are going to create shadows if you hang the lights up high.

Light placement is just as important as light type

TheBarn · Jul 5, 2018

Yes, I plan on leaving the ceiling open. The bottom chord of the truss is 12' above the floor. I planned on hanging the fixture so that the light is at the same height as the base of the bottom chord, 12'.

Lelandwelds · Jul 5, 2018

wssix99 said:
You need regular fixtures also and NOT "high bay." High bay situations are like what you see in big box stores: (12' is way short of that)

High bay fixtures just have a narrow angle off the reflectors, so with if you mount them too low, you'll get inconsistent lighting and issues with shadows.

The lights the OP is looking at are not the classic high bay from days past. The don't really have reflectors or optics. The may use a tighter beam on the LED itself but that will only be 15° or so and not a big deal. They need only be mounted higher because they're pretty bright.

His mounting height and two fixture wattages are right in the middle of several acceptable choices. If he changed his colors, surfaces, or mounting height a bit the other light becomes a better choice.

He is trying to predict which choice is freaking awesome and which is damn impressive. Too bad you can't install both and flip on "A", then "B", like the eye doctor does.

Lelandwelds · Jul 5, 2018

Which tractor? Early JD 1050?

TheBarn · Jul 5, 2018

Lelandwelds said:
Which tractor? Early JD 1050?

John Deere 830. Three cylinder diesel manufactured in the mid 70s, about 35hp at the PTO.

Platonic Solid · Jul 5, 2018

Lelandwelds said:
...
He is trying to predict which choice is freaking awesome and which is damn impressive. Too bad you can't install both and flip on "A", then "B", like the eye doctor does.

Actually, he can have the best of both worlds with the 110W. He gets bang-for-buck bragging rights and if he decides it's too fricken bright, then just wire all the violet and grey wires to a dimmer (link). :thumbup:

TheBarn · Jul 5, 2018

Platonic Solid said:
Actually, he can have the best of both worlds with the 110W. He gets bang-for-buck bragging rights and if he decides it's too fricken bright, then just wire all the violet and grey wires to a dimmer (link).

Thanks for the dimmer link. If I layout the lights in 3 rows of five lights, but want to have two lighting circuits, lets say the front 9 lights on one switch and the rear 6 lights on another switch, I would still only use one dimmer, correct?

MFolks · Jul 5, 2018

If you can paint the walls white,it will greatly help,a gloss or semi gloss seems to work the best.

Platonic Solid · Jul 5, 2018

TheBarn said:
Thanks for the dimmer link. If I layout the lights in 3 rows of five lights, but want to have two lighting circuits, lets say the front 9 lights on one switch and the rear 6 lights on another switch, I would still only use one dimmer, correct?

Correct. The dimmer circuit is completely independent of the power circuit. You can have as many On/Off switch zones as you like and still only need 1 dimmer. What you cannot do is put more than 1 dimmer per fixture.

Platonic Solid · Jul 5, 2018

MFolks said:
... a gloss or semi gloss seems to work the best.

That's a common misconception. Flat and eggshell actually works best. Look up the difference between specular and diffused reflectance.

yeldogt · Jul 5, 2018

Platonic Solid said:
Actually, he can have the best of both worlds with the 110W. He gets bang-for-buck bragging rights and if he decides it's too fricken bright, then just wire all the violet and grey wires to a dimmer (link).

don't you find those overly bright ? Maybe just me .. but I hate space with what amounts to sun spots.

wssix99 · Jul 5, 2018

TheBarn said:
Ok, I will look into that. I had seen some builds on the light fixture layout thread where the 80w high bays were used with a 10' ceiling height. I will look into regular fixtures for my application too. Thanks.

They list a minimum height of 10' and give a range of 10' - 40':
http://www.acuitybrandslighting.com/library/ll/documents/specsheets/ibhst.pdf

Depending on your temperature situation (reading the fine print), you may also need to drop the fixture 18" from the ceiling.

Like the picture I posted, Lithonia also gives big boxes and gyms as the sample for the product: http://www.lithonia.com/commercial/ibh.html#.Wz7W54h4eUk

So - you could install these at 12', but a normal fixture (where you are at the top of the height range) should perform better for you than a high bay fixture (where you are at the bottom of the height range).

I like the sunburn theory that many of our friends post about here. (If you save on the fixture type, you can install more - to the point where all the light will give you a sunburn.)

Platonic Solid · Jul 6, 2018

You have to weigh all variables: application, environment, visual acuity of occupants, beam spread, glare, fixture cost, fixture life expectancy, installation cost, energy cost. We are seeking 93fc @ 30" workplane in a low reflectance occasional use general mechanical work environment with an occupant of unknown visual acuity. Yes, using more 10,400 lumen fixtures will yield more even distribution at higher cost. Only the end user can make these decisions. I've found most are seeking the best bang for the buck and the 110W Greentek fits that bill in this application. I would not recommend a layout using higher lumen output and/or fewer than the 15 fixtures discussed.

The term High Bay for some of these fixtures is misleading. A 10,400 lumen 80W fixture with medium beam spread would only be used above 12ft for lower fc @ workplane requirements in areas without isles. Notice that Lithonia offers narrow and medium distribution (referenced incorrectly in the beginning of their spec sheet as wide). The GreenTek and LumeGen are medium beam spread fixtures, which is ideal for the OPs height and application.

Yes, you can use 4ft strip lights at 12ft, but it's not cost effective for this application.

Lelandwelds · Jul 6, 2018

Platonic Solid said:
You have to weigh all variables: application, environment, visual acuity of occupants, beam spread, glare, fixture cost, fixture life expectancy, installation cost, energy cost. We are seeking 93fc @ 30" workplane in a low reflectance occasional use general mechanical work environment with an occupant of unknown visual acuity. Yes, using more 10,400 lumen fixtures will yield more even distribution at higher cost. Only the end user can make these decisions. I've found most are seeking the best bang for the buck and the 110W Greentek fits that bill in this application. I would not recommend a layout using higher lumen output and/or fewer than the 15 fixtures discussed.

The term High Bay for some of these fixtures is misleading. A 10,400 lumen 80W fixture with medium beam spread would only be used above 12ft for lower fc @ workplane requirements in areas without isles. Notice that Lithonia offers narrow and medium distribution (referenced incorrectly in the beginning of their spec sheet as wide). The GreenTek and LumeGen are medium beam spread fixtures, which is ideal for the OPs height and application.

Yes, you can use 4ft strip lights at 12ft, but it's not cost effective for this application.

Ugh, variables. Diffused reflectance was a bigger topic than i expected. The bit about why snow is white and moon plains are dark was interesting. We are learning here!

I keep forgetting about dimmers. Kinda makes it hard to miss your target. If needs change, you can fine tune a bit.

wssix99 · Jul 7, 2018

Platonic Solid said:
The term High Bay for some of these fixtures is misleading. A 10,400 lumen 80W fixture with medium beam spread would only be used above 12ft for lower fc @ workplane requirements in areas without isles. Notice that Lithonia offers narrow and medium distribution (referenced incorrectly in the beginning of their spec sheet as wide). The GreenTek and LumeGen are medium beam spread fixtures, which is ideal for the OPs height and application.

Right, the term doesn't mean much, but Lithonia still intends these fixtures for an industrial setting. If the OP is going to create work spaces along the walls and work on equipment off of the floor, (and given the non-reflective surfaces) I would think that something with a wide beam angle would fill the room better.

It seems that Lithonia doesn't even "go here" yet. I don't see any of their "industrial" LED fixtures in anything but a Medium or Narrow beam angle. It seems that they want us to go to their regular florescent fixtures for workspace lighting.

Platonic Solid · Jul 7, 2018

wssix99 - Wide distribution is for low mounting heights or if you want more light higher on the walls (which most don't). Medium distribution is ideal for most garages with ceilings 10ft+. 15 medium distribution fixtures in a 30x64x12 space is the absolute minimum - it's actually below the minimum hence OP will have somewhat uneven distribution. The spacing criterion for these fixtures is 1.25. Calculation for max fixture spacing = 12ft (fixture mounting height from floor to luminous opening) - 2.5ft (workplane height) = 9.5ft x 1.25 (SC) = 11.875. Rounding up to 12ft spacing is no big deal, but distribution becomes less even beyond that.

The OPs 3 rows of 5 exceeds this criteria. 3 rows of 6 would solve that problem. Now if you want to reduce shadows and limit the need for task lighting along wall mounted workbenches we need to jump to 4 rows of 6 using the 80W 10400 lm fixtures which yields 93fc. 4 rows of 7 is more even and yields 108fc @ workplane (this would be my preference for this space).

TheBarn - If you want to know ideal spacing for 4 rows of 7 10400 lm fixtures, just plug the rows and column numbers into the visual tool and check the layout box on the right.

Lelandwelds · Jul 7, 2018

Platonic,
Three rows of 5 @ 110 watt isn't quite enough?
3 rows of 6 @ 80w attached is acceptable
4 rows of 6 @ 80 watt is better yet
4 rows of 7 @ 80 watt is optimal?

I am sure the above is your sense of professional perfectionism coming to the front but aren't the last two a tiny bit excessive?

Wouldn't a cheap 20 watt LED strip or so at six feet over a bench provide plenty of task lighting with option #2? Formaspace sells custom workbenches for every imaginable kind of lab, tech, and factory settings. Many of them are set up similiar to what I propose.

Platonic Solid · Jul 7, 2018

Lelandwelds said:
Wouldn't a cheap 20 watt LED strip or so at six feet over a bench provide plenty of task lighting with option #2?

Absolutely, that's why I said "... if you want to reduce shadows and limit the need for task lighting along wall mounted workbenches ...". The problem with only 3 rows at 30ft width is you'll still end up with shadows between a car and the wall.

Edit - that last sentence isn't correct. I was thinking 36ft when I typed it. At 30ft you can mount the fixtures 4ft from the walls and still maintain spacing criteria.

Platonic Solid · Jul 8, 2018

To determine which layout is best for this space requires proper cost benefit analysis weighing frequency of use and budget.

If used less than 20 hrs./wk and keeping cost down is important, then
3x5 GreenTek layout works ($1250)(93fc)(Max/Min 3.19).

For 20+ hrs./wk either
3x6 GreenTek ($1500)(111fc)(Max/Min 2.97) or
4x6 LumeGen ($1680)(93fc)(Max/Min 2.89).

For 40+ hrs./wk either
4x6 Greentek ($2000)(147fc – dimming is a must for this one)(Max/Min 2.89) or
4x7 LumeGen ($1960)(108fc)(Max/Min 2.74).

Since the cost difference between the 4x6 GreenTek and 4x7 LumeGen is only $40, I would scrap the 4x7 LumeGen plan in favor of the 4x6 GreenTek. The slightly more even distribution with the 4x7 Layout isn’t worth it. Put the GreenTeks on dimmers and you’ll greatly extend fixture life. As they get dirty and old (and you get old) just turn them up. Same analogy can be applied to 3x6 GreenTek vs 4x6 LumeGen.

Max/Min figures above are the ratio of max fc divided by min fc at workplane. Ratio below 3.00 recommended to reduce eye strain. This is why frequency of use matters. The more time you spend in an unevenly lit environment, the more likely you are to experience eye fatigue which can lead to headaches.

So now that I’ve done all the work, I’d say 3x6 GreenTek is the sweet spot on this one. I’d still install a dimmer.

Yes I could just have posted that 3x6 GreenTek is the sweet spot, but then you wouldn’t see the process you have to go through to get there.

Lelandwelds · Jul 8, 2018

I don't know if you just love this stuff or are fulfilling a secret wish to be an educator but thanks for the time and effort. My noggin needs new ideas to be pounded in.

I have looked at a bunch of spaces for lighting ideas. When they got it mostly ok, the lighting is just an unnoticed background object. When it is bad, it's annoying and I can think of a dozen places i'd rather be. When they nail it, everything looks cleaner and the space bigger.

Pretty important for a switch I used to flip without thinking.

Platonic Solid · Jul 8, 2018

Lelandwelds - I've probably been doing this too long.

Just for the heck of it here's how 4ft 2lamp 2640 lm per bulb (5280 lm per fixture) turns out:

6x10 (~$1800)(98fc)(Max/Min 2.56)

Lelandwelds · Jul 8, 2018

Platonic Solid said:
Lelandwelds - I've probably been doing this too long.

Just for the heck of it here's how 4ft 2lamp 2640 lm per bulb (5280 lm per fixture) turns out:

6x10 (~$1800)(98fc)(Max/Min 2.56)

Sixty?!! I bet it's evenly lit but my fingers hurt just thinking of it. With that many you still need to space them 2 ft apart in rows 2 ft apart? Four feet from walls?

If you substituted those edge lit panels, your ceiling would be almost entirely covered in fixtures!

Toomanytools? · Jul 8, 2018

This is why I don't have lights up yet, you think you have an answer then nope something better comes along.
We all have very similar buildings mine is two buildings a 36'x56'x15'6" and a 24'x48'x10'6". The bigger is RV and truck parking with an area of metal fab, the smaller a wood working shop. There must be a handful of fixtures that work best and come at an affordable price ( most of us are low on funds at this point). I'll be watching for your decision hopefully to get some insight. Right know trying to decide on soffit LED's can type or wafer?
Good luck

Platonic Solid · Jul 9, 2018

Toomanytools? - You'll be working in the dark for a long time if you're waiting for manufacturers to stop innovating. The first decision you'll need to make is whether the "parking only" area is to be exclusive for that purpose only as you don't need much light to park.

Toomanytools? · Jul 9, 2018

PS, innovation waits for none. It just seems I have a clear choice then wait too long and that fixture is no longer available. I would like the parking space to be around 80fc I'm thinking, then a section 30x18 to be a bit more were I will work. The Woodshop needs to be in the high 90's to 100.

wssix99 · Jul 11, 2018

Innovation waits for none, but it gets a lot less expensive as time goes on. lol

Lelandwelds · Jul 14, 2018

Toomanytools? said:
e. I would like the parking space to be around 80fc I'm thinking, then a section 30x18 to be a bit more were I will work. The Woodshop needs to be in the high 90's to 100.

Thats pretty bright for car storage unless you spin wrenches too. I dont know. I think different lighting in parts of one big room may cause some eye strain? As often as not, my final use is much different from what I pictured when starting. Probably better to light it all well.

Sounds like one helluva space you're building!

Citation · Jul 14, 2018

TheBarn said:
I have a 30x64x12 pole barn with an unfinished interior with an open ceiling and exposed trusses. After reading over the Lighting Layout and Best Fixture Ever threads, I am deciding between the GreenTek 110w High Bays with 16,400 lumens or the 80w LumeGen 10,400 lumen high bay. Sorry, but I don't have enough posts yet to give you the links. Thanks to Platonic Solid and all the others who have put their time and energy into those threads.

Is a 110 watt fixture appropriate for a 12' mounting height, or is the 80w a better choice?

Do the reflectance values change from 70/50/20 if the interior walls are light gray and there is no ceiling just exposed trusses and light gray underside of the roofing material?

Plugging in 70/50/20 into the visual 3d lighting tool, 15 (3 rows of 5) of the 110w Greenteks is 99 fc. Using IBH 18000LM SD080 MD OZ10 30K 80CRI as the comparable fixture.

Plugging in 70/50/20 with the 80w LumeGens requires 21 fixtures (3 rows of 7) for 93 fc. Using IBH 12000LM SD080 MD OZ10 30K 80CRI as the comparable fixture.

Essentially, the 110w GreenTeks seem like the correct choice, but I am not sure if I am looking at this correctly with regards to ceiling height.

Thanks for your help!

Totally unrelated but is that a JD 1020 tractor?

markietas · Jul 15, 2018

wssix99 said:
You need regular fixtures also and NOT "high bay." High bay situations are like what you see in big box stores: (12' is way short of that)

High bay fixtures just have a narrow angle off the reflectors, so with if you mount them too low, you'll get inconsistent lighting and issues with shadows. This will probably be enhanced because the rooms reflectivity.

Regular fixtures should also be a lot less expensive!

I agree, Also I have a 11ft ceiling and using these 40w led fixtures I can't imagine having something brighter at the same height. Also I highly recommend them, at only $25 ea.

https://www.ruralking.com/4-led-shop-light-4500-lumens

wssix99 · Jul 15, 2018

markietas said:
I agree, Also I have a 11ft ceiling and using these 40w led fixtures I can't imagine having something brighter at the same height. Also I highly recommend them, at only $25 ea.

https://www.ruralking.com/4-led-shop-light-4500-lumens

Platonic Solid brought up a good point regarding the OP's goals and I think the question is still on the table as to if the OP wants to use this as floor lighting only or also as task lighting for the space.

80w or 110w LED High Bay for 30x64x12?

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